The invention relates generally to methods and systems for, independently and automatically, filling canisters from a common set of pressurized storage stations arranged in a priority cascaded manner.
Numerous types of canisters exist for storing pressurized gas, such as anesthesia, air, oxygen, carbon dioxide, nitrogen, compressed natural gas (CNG) and the like. One example of a canister is a self-contained breathing apparatus (SCBA) which may be used in various applications, such as by firefighters, in medical applications, in recreational underwater diving applications and the like. Various systems exist for filling the canisters with the appropriate type and amount/pressure of gas.
Heretofore, a manual filling system has been utilized in firefighting applications to refill firefighter SCBA canisters on-site at a fire, emergency or other catastrophic event. In firefighter applications, a fire truck or other vehicle carries recharging storage tanks that are arranged in different stages. The stages are prioritized, such that the primary stage is first used to fill canisters, before tapping secondary or tertiary stages. The secondary stage is used to fill canisters before the tertiary stage. The secondary and tertiary stages are only utilized when the primary stage lacks sufficient pressure to entirely fill the canister. The storage stages have separate manual control valves, outputs of which are joined to at least one fill station. Firefighters manually couple and decouple each SCBA canister to the fill station.
Typically, first and second fill stations are provided on opposite sides of the vehicle, while a third fill station is provided at the rear of the vehicle. During a fire, firefighters manually attach each canister to one of the fill stations at the vehicle containing the recharging storage tanks. Once the canister is attached to the refilling system, the firefighter determines the pressure within the canister (by reading a regulator) and based thereon, determines which of the primary, secondary and tertiary fill stages or stations should be utilized to fill a canister.
For example, a used canister may have air pressurized to less than 1000 psi, while it is desirable to fill the canister up to 4500 psi. As an example, it may be assumed that the primary storage station has air pressurized to approximately 3000 psi, while the secondary and tertiary stations have air pressurized to 4000 psi and 6000 psi, respectively. The firefighter would manually open a valve to permit the primary storage station to fill the canister to approximately 2500 psi. The firefighter would then close the valve associated with the primary storage station, and next open the valve associated with the secondary storage station. Once the canister is charged to the pressure of the primary storage station, and primary storage station valve is closed, the firefighter would then open the valve associated with the secondary storage station in order to charge the canister up to approximately 3500 psi. Once the pressure reaches approximately 3500 psi, the firefighter then closes the valve associated with the secondary storage station and opens the valve associated with the tertiary storage station in order to complete charging of the canister to the 4500 psi in the present example.
As the primary, secondary and tertiary storage stations are used, the pressure of the air contained therein falls. The primary storage station will have air pressurized to a lower level than the secondary storage station which will have air pressurized lower than the third storage station due to the practice of beginning a canister filling process from the storage station having an air pressure that is lowest of the storage stations, but greater than the initial pressure in the canister.
To perform the above process, firefighters separately couple one or more canisters to the fill stations at the rear of the vehicle and one or more canisters to each of the fill stations of either side of the vehicle. The firefighters repeat the above priority filling process for each canister. The term “priority filling” refers to the practice of prioritizing the storage stations and filling each canisters initially from a designated first or primary storage station, then from a second or secondary storage station, etc. While all of the storage stations may initially charged to a common pressure, the foregoing priority filling process causes the storage stations to differ from one another by varying degrees throughout use.
The foregoing conventional priority filling process was performed manually, in that a firefighter or a team of firefighters working in cooperation, must monitor the pressure within each canister and each storage station and manually open and close valves to utilize the storage stations in a desired priority filling sequence when filling canisters.
However, the conventional manual process has experienced several limitations. Among others, the canister filling system (such as carried by a firefighting vehicle) was typically operated by personnel who continuously attach and decouple canisters and open and close valves for the storage stations. The conventional on-site SCBA canister filling process is slow as it typically requires each a series of valves to be opened and closed manually in order to complete the fill process, which may result in firefighters waiting for new SCBA canisters to be filled without being able to assist in fighting a fire. In addition, conventional on-site SCBA canister filling stations generally involve at least one firefighter operating each of the fill stations in the priority filling order.
A need remains for an improved canister filling method and system.